QTL Underlying Androgenic Haploid Production in Pepper (Capsicum annuum)

The use of doubled haploids (DH) to accelerate homozygous line production is a valuable tool in plant breeding programs. A limitation to the utilization of DHs in pepper (Capsicum annuum) breeding is the variability and unreliability among genotypes of plant regeneration from anther culture. A classical genetics approach, recombinant inbred lines (RILs) derived from a cross between regeneration-responsive and regeneration-unresponsive lines, was used to determine if haploid regeneration from microspores is a quantitative trait controlled by genetic loci. Transcriptome sequencing of the RIL parental lines was used to develop 400 SNP assays that were used to genotype 200 F5 RILs. Phenotyping of three F6 individuals (three reps) from each of the 200 RILs indicate six QTL, four controlling embryogenesis and two controlling plantlet regeneration. Two of the six QTL showed a positive effect on the phenotype coming from the regeneration-unresponsive line, contributing to both embryogenesis and plantlet regeneration. This is consistent with heterosis that was observed in the F1 and the transgressive segregation observed in the RIL population.